camera.py

from flask import (
    Blueprint, jsonify, flash, g, redirect, render_template, request, url_for, send_file
)

from picamera import PiCamera
import time
import io

bp = Blueprint('camera', __name__)

@bp.route('/camera/current')
def get_picture():
    stream = io.BytesIO()
    camera = None

    try:
        camera = PiCamera()

        camera.start_preview()
        time.sleep(2)
        camera.capture(stream, 'jpeg')
        camera.stop_preview()
        camera.close()

        stream.seek(0)
        return send_file(
                          io.BytesIO(stream.read()),
                          mimetype='image/jpg')
    except:
         if camera is not None:
             camera.close()
         raise Exception("Camera is all messed up yo!")